Single-molecule magnets (SMMs) are molecules that behave like nanoscopic bar magnets. They are interesting due to various potential applications in high-density information storage, molecular spintronics, and magnetic refrigeration. The challenge in realizing these applications lies in designing molecular magnets that have much higher operating temperatures than have been obtained currently.
Lanthanide ions are particularly well-suited for the design of effective SMM because of their high magnetic anisotropic nature. This property inherently possessed by the lanthanide metals arise from unquenched orbital angular momentum and strong spin-orbit coupling. In order to suppress quantum tunneling relaxation processes that leads to a shortcut of the maximum spin-relaxation barrier and thus, a weaker magnet, a strong exchange coupling is required between the spins. Therefore, a promising route to increase operating temperature of single-molecule magnet is to design lanthanide complexes that simultaneously feature high-magnetic anisotropy and strong magnetic exchange coupling. As a means of achieving strong coupling, radical-bridging ligands with diffused spin orbitals are employed in order to penetrate the core electron density of the deeply buried 4f orbitals within lanthanide ions. We are exploring the utility of various redox-active ligands for the design of radical-bridged multinuclear lanthanide single-molecule magnets.